Handle the specified Throwable encountered while processing
the specified Request to produce the specified Response. Any
exceptions that occur during generation of the exception report are
logged and swallowed.

Handle the HTTP status code (and corresponding message) generated
while processing the specified Request to produce the specified
Response. Any exceptions that occur during generation of the error
report are logged and swallowed.

Find and return the ErrorPage instance for the specified exception's
class, or an ErrorPage instance for the closest superclass for which
there is such a definition. If no associated ErrorPage instance is
found, return null.

Handle an HTTP status code or Java exception by forwarding control
to the location included in the specified errorPage object. It is
assumed that the caller has already recorded any request attributes
that are to be forwarded to this page. Return true if
we successfully utilized the specified error page location, or
false if the default error report should be rendered.